Opportunities for Incorporating Performance Evaluation ... · Example: IPas2 Software (UWMARC ) 2D Scan of mix image using bench top scanner. Sefidmazgi, N. R., Tashman, L., and Bahia,

Opportunities for Incorporating

Performance Evaluation into Mix Design,

Construction, and Acceptance

By

Andrew Hanz, Ph.D.

Gerald Reinke

MTE Services Inc.

July 17, 2014

HMA Monitoring and AcceptanceVolumetric Properties

Mix Composition

Moisture Damage

In-Place Density

Smoothness

Distress Test

Rutting Hamburg, FN

FatigueBeam, SCB,

Uniaxial, IDT

Thermal

Cracking

Dc(t), IDT,

ATCA

Design E*

• Daily Sampling: Surrogate

tests to estimate

performance.

• Mechanical Testing: Verify

properties measured in mix

design at a reasonable

sampling frequency.

• Frequency: Point vs.

Continuous measures (i.e.

PSPA and IC)

• Type: Destructive vs.

Non-Destructive

Mathy Technology & Engineering

Performance Evaluation in Mix Design

1. Materials Selection

2. Design Aggregate Structure

3. Determine Optimum AC

4. Moisture Damage Evaluation

5. Design Input

• PG Selection to account for RAP/RAS

− Assess need for “Grade Dumping”

− Evaluate different oil modifications.

− Obtain better estimate of rheological

properties.

• Balanced Mix Design Concept

− Maximum Rutting Limit

− Minimum Fracture Energy for Fatigue

and Thermal Cracking (northern states?)

− Must meet both volumetric and

performance criteria.

• Modulus Value for M-E Design

− Modeling: Hirsch/Witzcak

− Direct Measurement


Binder Evaluation for High RAM Mixes

Direct Measurement

– 4mm PP

Extrapolation of 8

mm Data

Effect of Aging

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

OB RTFO PAV1 PAV2

Rh

eo

log

ica

l In

de

x (

R)

20%RAS+ 5% Oil 1 20%RAS+5%Oil 2PG Grading

-40.0

-34.0

-28.0

-22.0

-16.0

OB RTFO PAV1 PAV2

Bin

de

r LT

PG

Gra

de

20% RAS +5% Oil 1 20% RAS + 5% Oil 2

1. Anderson, et al., “Binder Characterization and Evaluation – Volume 3: Physical Characterization.” SHRP A-369

Report, National Research Council, 1994.

2. Farrar, Sui, et al. 4 mm Plate Development – TRB 2011, 2012, Eurobitume 2012 and others.Mathy Technology & Engineering

Application and Verification - Trial

Section US Hwy 14

• 4 mixes placed on shoulders in Sept. 2012– PG 58-28, 0% RAS, 20% RAP, (21% PBR) – JMF

– PG 58-28, 0% RAS, 31% RAP, (32% PBR)

– PG 58-28, 6% RAS (22% PBR), 11% RAP (12% PBR)

– PG 52-34, 6% RAS (22% PBR), 11% RAP (12% PBR)

• Field Cores– 1 month after construction – aged 0, 5, and 10 days at 85°C.

– 1 year after construction – No aging, top 12mm and 2nd 12mm tested.

• Testing

– Mix stiffness – torsion bar

– Recovered Binder Properties – 4 mm DSR

– Chemical Analysis - Iatroscan

For more information: Reinke, et. al., “Impact of RAS on Mixture and Recovered Binder

Properties, Paper 1172, ISAP 2014.Mathy Technology & Engineering

-2.3-2.7

-6.8

0.4

-0.7

-2.9

0.0

-0.6

-2.0-1.8

-2.6

-5.7

-8

-7

-6

-5

-4

-3

-2

-1

0

1

15 17 19 21 23 25 27 29

ΔT

C (

M C

RIT

ICA

L T

EM

P -

S C

RIT

ICA

L T

EM

P, °

C) ASPHALTENE, %

Hwy 14 11% RAP, 6% RAS, PG 58-28 Hwy 14 31% RAP, 0% RAS PG 58-28

Hwy 14 20% RAP, 0% RAS, PG 58-28 Hwy 14 11% RAP, 6% RAS, PG 52-34

THE MORE NEGATIVE THE

DIFFERENCE OF M - S

CRITICAL TEMPERATURES

THE MORE M CONTROLLED

IS THE BINDER

UNAGED

10 DAY

5 DAY

Note: data values in colored boxes are

the M-S critical temperatures for the

respectively colored data curves at 0,

5 and 10 days of core aging @ 85°C


Effects of Aging on Mechanical Properties

and Chemistry

How does laboratory aging protocol relate

to the field?

MIX TORSION BAR TEST – ASTM D7552

≈50 mm X 12 mm X 7 mm

TESTED AT -40°C TO +40-80° DEPENDING ON

MIX STIFFNESS

Data available:

• 2012 Cores: Taken one month after construction and aged at 85°C for 0, 5, and 10 days.

• 2013 Cores: Taken one year after construction and tested.

Objectives

• Verify that the aging conditions selected are representative of what occurs in the field.

• Compare results of field aged RAP/RAS mixes to laboratory aged core results.

*Will focus on low frequency end of master curve to compare values of stiffness.

1.0E+05

1.0E+06

1.0E+07

1.0E+08

1.0E+09

1.00E-07 1.00E-06 1.00E-05 1.00E-04 1.00E-03 1.00E-02 1.00E-01 1.00E+00 1.00E+01 1.00E+02 1.00E+03

ST

IFF

NE

SS

MO

DU

LUS

G*

, P

a

FREQUENCY, RAD/SEC

G* FOR 6% RAS, 11% RAP MIXES PG 58-28 @ 0, 5 & 10 DAYS AGING @ 85°C 2012 and Cores

from 2013

Data for 2013 cores - - -

Data for 2012 cores


The mix stiffness data for the PG 58-28 mix shows that

the modulus of the top 12 mm of the ≈ 1 year old field

mix is the same or a greater than the 5 day aged

original mix while the 2nd 12 mm layer is similar to the

stiffness of the 5 day aged mix.

2012 Core – 0 Day Aging @ 85°C 2013 Core - Top 12mm – Rep 1

2012 Core – 5 Day Aging @ 85°C 2013 Core – Top 12 mm – Rep 2

2012 Core – 10 Day Aging @ 85°C 2013 Core – 2nd 12 mm


1.0E+05

1.0E+06

1.0E+07

1.0E+08

1.0E+09

1.00E-07 1.00E-06 1.00E-05 1.00E-04 1.00E-03 1.00E-02 1.00E-01 1.00E+00 1.00E+01 1.00E+02 1.00E+03

CO

MP

LEX

SH

EA

R M

OD

ULU

S,

G*

, P

a

REDUCED FREQUENCY, RAD/SEC

Effect of Reducing Binder Grade: G* for 6% RAS, 11% RAP MIXES PG 52-

34 @ 0, 5, 10 DAYS AGING 2012 CORES and CORES TAKEN in 2013

Data for 2013 cores - - -

Data for 2012 cores

The mix stiffness data for the PG 52-34 mix shows that the

modulus of the top 12 mm of the ≈ 1 year old field mix is

the same or a little greater than the 5 day aged original

2012 Core – 0 Day Aging @ 85°C 2013 Core - Top 12mm – Rep 1

2012 Core – 5 Day Aging @ 85°C 2013 Core – Top 12 mm – Rep 2

2012 Core – 10 Day Aging @ 85°C 2013 Core – 2nd 12 mm

Summary of Findings

• Aging– Consideration of multiple aging conditions is necessary. Aging vs. ΔTc

relationship was not linear.

– Study was focused on mixtures and recovered binders to best simulate

thin film condition in the field. Can also study relationships with RTFO

and PAV aging of binder.

• Effects of RAP and RAS

– For a given binder replacement, the rate of aging and embrittlement

of high RAP mixes was significantly lower relative to RAS.

– This can be remedied by softening the binder grade and/or use of

rejuvenating additives.


Balanced Mix Design Concept

HT (~50°C)IT (15-25°C)

Rutting Hamburg or FN

Fatigue Semi-Circular Bend

LT (-22 to -34°C)

Thermal CrackingTSRST or DC(t)


Balanced Mix Design

Challenges

• Corrective Action

– Binder vs. Aggregate

Structure Contribution

• Field Verification

– σTest vs. σProduction

– Lab vs. Field Aging

– Surrogate test methods

Cooper, S. “Testing and Analysis of LWT and SCB Properties of Asphalt Mixtures” Louisiana

Transportation Conference, 2013.

1. Establish AC content by volumetrics

2. Verify Performance


Effects of Aggregate Structure and Binder

Properties on LWT

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

RU

T D

EP

TH

IN

mm

@ 1

00

00

HA

MB

UR

G P

AS

SE

S

0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0

SVFSVFSVFSVF

1 E-1 FINE @ 890 N--R2=0.82

2 E-10 COARSE @ 890 N--R2=0.72

3 E-1 FINE @ 703 N--R2=0.88

4 E-1 FINE @ 534 N--R2=0.79

5 E-10 FINE @ 534 N--R2=0.88

6 E-10 FINE @ 703 N--R2=0.89

7 E-10 FINE @ 890 N--R2=0.74

8 E-10 COARSE @ 534 N--R2=0.93

9 E-10 COARSE @ 703 N--R2=0.86

RUT DEPTH AS A FUNCTION OF SVF

FOR ALL MIXES FOR ALL TEST LOADS

1111

5555

8888

6666

9999

4444

2222

3333

7777

1. E1 Fine @ 890N

2. E10 Coarse @ 890N

3. E1 Fine @ 703N

4. E1 Fine @ 534N

5. E10 Fine @ 534N

6. E10 Fine @703N

7. E10 Fine @890N



SVF = η* x Stress at

70% η*initial

Reinke, G., et al. “Utilization of Binder Stress Sensitivity to Investigate the Impact of Applied

Load, Binder Type, and Aggregate Structure on the Rutting Behavior of Bituminous

Mixtures.” Eurobitume, 2008.

Higher η and more stress tolerance =

better rutting resistance


Aggregate Structure Effect on Thermal-

Volumetric Properties

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

-60 -40 -20 0

Thermal Strain (%)

Temperature (°C)

High

connectivity

Low

connectivity

Bahia, Hanz, Roohi, “UW-MARC Mixing and Compaction Temperature Workshop” UW

Madison, 2012-2013.


Direct Measurement of Aggregate

Structure – Image Analysis

Example: IPas2 Software (UWMARC)

2D Scan of mix image using

bench top scanner.

Sefidmazgi, N. R., Tashman, L., and Bahia, H., "Characterization of Asphalt Mixture Rutting

Performance Using 2-D Imaging Internal Structure Parameters," Journal of the Association

of Asphalt Paving Technologists, Vol. 81, 2012, pp. 109-137.


Relations to Performance – Image

Analysis

R² = 0.90

1

10

100

1000

10000

-500 500 1500 2500 3500 4500

Flo

w N

um

ber

Contact Length (mm/100cm^2)

E3 E10 E30

3.00E-05

3.50E-05

4.00E-05

4.50E-05

5.00E-05

5.50E-05

6.00E-05

6.50E-05

25000 30000 35000 40000 45000 50000

CT

E (

1/°

C)

Contact Length

Rutting Resistance Thermal Contraction

1. Sefidmazgi, N. R., Teymourpour, P., Bahia, H. U. " Effect of Particle Mobility on Aggregate Structure Formation in

Asphalt Mixtures, "Journal of the Association of Asphalt Paving Technologists, Vol. 82, 2013, pp. 16-34.“

2. Teymourpour, P.; Bahia, H.U.; "Role of Asphalt Modification In Achieving Better Aggregate Packing Structure And

Performance," Proceedings of the 58th Annual Conference of the Canadian Technical Asphalt Association

(CTAA), 2013.


Direct Measurement of Aggregate Structure –

Shear Forces during Compaction

• http://www.troxlerlabs.com/products/5850.php

• http://www.pineinstrument.com/test/AFG2_superpa

ve_gyratory_compactor_T312_asphalt/main


Eccentricity

��

��

Relation to Mix

Stabilitye = Eccentricity

P = Pressure in the Gyratory

A = Sample Area

h = Sample Height

Relations to Performance – Shear

Measurement During Compaction

y = 1.0541x + 57.333

R2 = 0.809

0

2000

4000

6000

8000

10000

12000

0 2000 4000 6000 8000 10000

FN

TF

I

eR

Ram

GLPA

Mold

HMA Sample

o1.25

Faheem, Bahia, “Using the Gyratory Compactor to Measure the Mechanical Stability of

HMA Mixtures.” Wisconsin Highway Research Program, WisDOT, 2004.


Example: Inconsistent Stability During

Production

0.50

0.60

0.70

0.80

0.90

1.00

1.10

1.20

1.30

1.40

1.50

0 50 100 150 200 250 300 350 400

'e'

(in

ches

)

Count

075.1 E1 Wimmie 075.2 E1 Wimmie 075.3 E1 Wimmie

075.4 E1 Wimmie 075.5 E1 Wimmie 075.6 E1 Wimmie


Summary of Findings

• Performance related test methods for asphalt characterization are well established.

• There are opportunities to move beyond classifying aggregate structure based solely on gradation (i.e. fine and coarse) or mix classification (i.e. E1 vs. E10).

• These tools allow for assessment of how the aggregate and binder interact to form the final aggregate structure.


From Mix Design to Production –

Performance Testing Concerns

• Variability of Production vs. Test Method

– Is test sensitive enough to detect changes in mix

composition?

• Aging

– Short Term Aging: Protocol needed to ensure lab

and plant produced mixes experience similar aging

before testing.

– Long Term Aging: Aging protocol that relates to

critical condition in the field.

Effects of Variation in Dust and Asphalt

Contents on FN

Bonaquist, R., “Evalution of Flow Number as a Discriminating Mixture Property.”

Wisconsin Highway Research Program Report 0092-09-01, WisDOT, 2012


Effects of Deviation in Design Air Void

Content on FN

Bonaquist, R., “Evalution of Flow Number as a Discriminating Mixture Property.”

Wisconsin Highway Research Program Report 0092-09-01, WisDOT, 2012

Poor relationship

indicates that controlling

air void content during

production does not

necessarily ensure

rutting resistance.

Samples taken from

resulting changes in air

void content from

varying P200 and %AC


Short Term Aging - Preliminary Results:

Capitol Dr. Field Project

0

50

100

150

200

250

300

350

400

Design Day 1 Day 2 Day 3

Flo

w N

um

be

r (F

N)

Bonaquist, Bahia, Hanz, Velasquez, “WHRP Project 0092-12-02” Research in Progress, final

report under review. http://wisdotresearch.wi.gov/project?id=806


Long Term Aging Concerns

-8

-7

-6

-5

-4

-3

-2

-1

0

1

0 5 10

ΔTc

= m

(cri

t) -

S(c

rit)

Days Mix Aging at 85°C

PG 58-28,20% RAP, 0% RAS PG 58-28, 31%RAP, 0%RAS

PG 58-28, 11% RAP, 6% RAS PG 52-34, 11% RAP, 6%RAS

Recall – data from Slide 6

Does evaluating cracking resistance on plant produced samples or

even after 5 days aging represent possible differences in

performance late in service life? Research needed.Mathy Technology & Engineering

Example: Framework for Performance

Related Mix EvaluationMix

CharacteristicMix Design Production (Daily)

Production (every

XX,000 tons)

Recycled

Materials

Rheology of extracted

binders at different aging.Gradation and %AC

Rheology of

extracted binder.

Volumetrics

Current specifications +

Imaging or Shear

Measurement

Current Specifications

Rutting

Resistance

LWT, FN or iRLPD on un-

aged sample @ 50°CImage analysis, shear

measurement, or

other methods

Mix Performance

TestFatigue Cracking

SCB @ PG IT after long

term aging

Thermal

Cracking

Dc(t) @ LT PG+10 after

long term aging

Notes:

1. Hamburg, Dc(t), and SCB are currently under consideration

by WisDOT for evaluation of high RAM mixtures.


Thank You!

Acknowledgements

• P3 Symposium

organizing committee.

• WHRP Flex TOC

• UW Modified Asphalt

Research Center

• Mathy

Construction/MTE

Andrew Hanz

MTE Services Inc.

608-741-6352

[email protected]


Opportunities for Incorporating Performance Evaluation ... · Example: IPas2 Software (UWMARC ) 2D Scan of mix image using bench top scanner. Sefidmazgi, N. R., Tashman, L., and Bahia,

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